A variety of devices have been proposed as apparatus for determining a human condition such as an arousal state, a psychological state, or a fatigue state, in order to be used for safety improvement or the like during driving. For example, an arousal determination method is a method of applying a predetermined stimulus to a man, e.g., a driver, letting the man perform a work such as a button operation against the stimulus, and estimating an arousal state, based on a reaction time thereof (e.g., cf. Japanese Patent No. 3369201).